JPH08262913A - Fixing roll - Google Patents

Abstract

PURPOSE: To provide an inexpensive fixing roll excellent in toner releasability and durability and capable of obtaining a high-quality picture. CONSTITUTION: A heat conductivity imparting layer 2 is formed on the outer periphery of a cylindrical shaft 1, an oil barrier layer 3 is formed on the outer periphery of the layer 2, and an oil swelling layer 4 is formed on the outer periphery of the barrier layer 3 to constitute a fixing roll. The swelling amt. of silicone oil in the layer 4 is set at 1-8wt.%, and further the oil swelling layer 4 is the outermost layer formed by the matrix material contg. fluorosilicone rubber (component A), a peroxide cross-linking agent (component B) and a filler (component C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roll used in electrophotographic copying machines, printers and the like.

[0002]

2. Description of the Related Art In a copying machine using an electrophotographic copying method, as a method for fixing a toner image transferred on a copy sheet, for example, the following toner fixing is performed by a heat roll fixing method. That is, toner is attracted to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum, and this toner is transferred onto the copy paper surface. Next, as shown in FIG. 2, halogen lamps 16a, which serve as heat sources,
Copy paper 1 on which the toner 14 is transferred in the direction of the arrow between a pair of fixing roll 6 and a pressure roll 7 having 16b.
3, the toner 14 is heated and melted, and the pressure between the pair of rolls 6 and 7 causes the toner 14 to penetrate into the copy paper 13 to fix the toner 15 (fixed image). In FIG. 2, 10 is an inlet side guide, 11 is an outlet side guide, and 12 is a separation claw.

An example of such a fixing roll 6 is as follows. On the outer circumference of the core
An example is a fixing roll (two-layer structure) in which an elastic layer made of silicone rubber is formed, and a release layer made of fluororubber is formed on the outer circumference of the elastic layer. A fixing roll in which an elastic body layer made of silicone rubber is formed on the outer circumference of the core metal, a fluororubber layer is formed on the outer circumference of the elastic body layer, and a silicone rubber layer is further formed on the outer circumference of the fluororubber layer. (Three-layer structure).

[0004]

On the other hand, in particular, in a full-color copying machine, the toner meltability in the fixing section is increased in order to improve the image reproducibility, and as a result, toner adheres to the surface of the fixing roll. There is a problem that it is difficult to obtain a clear image. Therefore, conventionally, in order to impart releasability to the surface of the fixing roll, silicone oil is applied to prevent the toner from adhering to the surface of the fixing roll. For example, in the fixing roll described above, since the outermost layer of the roll is formed of fluororubber, the ordinary silicone oil such as dimethyl silicone oil repels the oil, resulting in poor wettability to the outermost layer. . Therefore, a modified silicone oil is used to improve the wettability. However, since the modified silicone oil is expensive, the cost becomes high, and further, since the modifying group of the modified silicone oil is thermally deteriorated, the releasing action is deteriorated. Further, in the above fixing roll, by forming a fluororubber layer serving as a barrier layer for silicone oil in the intermediate layer, swelling due to silicone oil is limited to the outermost silicone rubber layer to ensure dimensional stability of the entire roll. It was done.
However, a wetting film of silicone oil is formed on the outermost silicone rubber layer, and excess silicone oil penetrates into the silicone rubber layer and swells itself, resulting in poor wear resistance and wear deterioration. Causes a problem in roll durability.

The present invention has been made in view of such circumstances, and an object thereof is to provide a fixing roll which is low in cost, excellent in toner releasability and durability, and capable of obtaining a high quality image.

[0006]

In order to achieve the above object, the fixing roll of the present invention has a heat conductivity imparting layer formed on the outer periphery of a shaft body and an oil barrier layer on the outer periphery of this heat conductivity imparting layer. And a swelling amount of silicone oil in the oil swelling layer is 1 to 8% by weight.
And the oil swelling layer is set to the following (A) to
It is formed of a matrix material containing the component (C). (A) Fluorosilicone rubber. (B) Peroxide type crosslinking agent. (C) Filler.

[0007]

In other words, the present inventors have conducted a series of studies in order to prevent deterioration of durability and obtain a fixing roll excellent in toner releasing property. As a result, an oil swelling layer formed of a matrix material mainly composed of fluorosilicone rubber [component (A)] was formed on the outermost layer of the roll, and the swelling amount of the silicone oil in this oil swelling layer was set within a specific range. The inventors have found that, when set, the toner releasability can be imparted by appropriate swelling of silicone oil, and at the same time, it is possible to prevent deterioration of durability, and the present invention has been reached.

Next, the present invention will be described in detail.

The fixing roll of the present invention comprises a shaft, a heat conductivity imparting layer formed on the outer periphery of the shaft, an oil barrier layer formed on the outer periphery of the heat conductivity imparting layer, and the oil barrier. It is composed of an oil swelling layer formed on the outer periphery of the layer.

As the shaft body, a metal substantially cylindrical body whose inside is hollowed out is usually used.

The heat-conductivity-imparting layer formed on the outer periphery of the shaft body is generally used in a fixing system in which a fixing roll is heated and pressure-bonded, and therefore has a heat resistance, a high heat conductivity, and flexibility from the viewpoint of silicone. It is formed using a forming material containing rubber as a main component.

The silicone rubber is not particularly limited, and conventionally known ones can be used. Above all, HTV type silicone rubber (high temperature cross-linking type silicone rubber)
Is preferably used, and examples thereof include methyl vinyl silicone rubber and phenylmethyl silicone rubber.

The material for forming the thermal conductivity imparting layer is
In addition to the above silicone rubber, heat resistant rubber such as ethylene-propylene rubber, acrylic rubber and fluorosilicone rubber may be used in combination, if necessary.

In addition to the above-mentioned silicone rubber which is the main component, a cross-linking agent, a filler, a catalyst and the like can be appropriately added to the material for forming the heat conductivity imparting layer, if necessary.

The oil barrier layer formed on the outer periphery of the heat conductivity imparting layer is for preventing the silicone oil, which has penetrated through the outermost layer and infiltrate, from infiltrating and swelling into the heat conductivity imparting layer as the inner layer. It is provided in. Therefore, the oil barrier layer is formed of a material having barrier properties against silicone oil, for example, a forming material containing fluororubber as a main component.

Examples of the above-mentioned fluororubber (component A) include binary vinylidene fluoride rubber, ternary vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, fluorophosphazene rubber, etc. Alternatively, they may be used in combination of two or more. In particular, it is preferable to use a binary vinylidene fluoride rubber or a ternary vinylidene fluoride rubber in terms of heat resistance, silicone oil resistance, and cost. When two or more kinds are used in combination, a suitable combination is a binary vinylidene fluoride rubber and a ternary vinylidene fluoride rubber.

In addition to the above-mentioned fluororubber, fluorosilicone rubber that does not swell with silicone oil is used. Such a fluorosilicone rubber is a type of fluorosilicone rubber represented by the following general formula (1).

[0018]

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In addition to the above-mentioned fluororubber which is the main component, a crosslinking agent, a filler, a catalyst and the like can be appropriately blended in the oil barrier layer forming material, if necessary.

The cross-linking agent is not particularly limited, and conventionally known ones can be used. For example, an amine-based crosslinking agent such as hexamethylenediamine carbamate and N, N′-dicinnamylidene-1,6-hexanediamine,
Benzoyl peroxide, dicumyl peroxide,
Examples thereof include peroxide-based crosslinking agents such as t-butylcumyl peroxide and bisphenol AF-based polyol crosslinking agents. These may be used alone or in combination of two or more. Among them, benzoyl peroxide is preferably used from the viewpoint of crosslinkability and adhesiveness.

The oil swelling layer formed on the outer periphery of the oil barrier layer comprises a fluorosilicone rubber (component A), a peroxide type crosslinking agent (component B), and a filler (component C).
Formed by a matrix material containing

The above fluorosilicone rubber (component A) is
It is a heat-crosslinking type and is shown in (2) below, for example.
Fluorosilicone rubber having a repeating unit is exemplified.
It For such fluorosilicone rubber,
The average molecular weight is 1 x 10 ^Five~ 8 × 10^FiveThe range of
Is preferably used.

[0023]

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In addition to the above fluorosilicone rubber,
Examples thereof include copolymerized fluorosilicone rubbers having the repeating unit shown in (3) below. Such a copolymerized fluorosilicone rubber has a weight average molecular weight of 1
It is preferable to use one having a range of × 10 ⁵ to 8 × 10 ⁵ .

[0025]

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Further, the oil swelling layer has a swelling amount of 1 when compared to the initial amount when immersed in silicone oil at 160 ° C. for 24 hours as a weight change due to absorption and swelling of silicone oil such as dimethyl silicone oil. The amount of increase is set in the range of 8 wt% (hereinafter abbreviated as “%”). This swelling amount (ΔW) is calculated by the following formula.

Swelling amount (%) = [(weight after immersion−initial weight) / initial weight] × 100

By setting the amount of swelling to the above value, it is possible to make the outermost oil swelling layer contain silicone oil, which is a releasing oil, to ensure good toner releasability, and at the same time, wear resistance. Will also improve.
When the swelling amount exceeds 8% and increases, on the contrary, the wear resistance tends to deteriorate and the durability tends to deteriorate.

The peroxide-based crosslinking agent (component B) used together with the above-mentioned component A is the same as the above-mentioned crosslinking agent used as the material for forming the oil barrier layer, and is not particularly limited, and conventionally known ones. Used. For example,
Benzoyl peroxide, dicumyl peroxide,
Peroxide type crosslinking agents such as t-butyl cumyl peroxide, 2,4-dichlorobenzoyl peroxide, m-toluoyl-benzoyl peroxide and 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane can give. These may be used alone or in combination of two or more. Among them, benzoyl peroxide is preferably used from the viewpoint of crosslinkability and adhesiveness. Thus, by using the peroxide-based crosslinking agent (component B) as the crosslinking agent, the liquid stability is good, the pot life is long, and the roll is long when the coating liquid is prepared at the time of forming the oil swelling layer described later. The manufacturing workability of is improved. In addition, the formation material is not wasted due to gelation, which leads to cost reduction. This is because the peroxide-based cross-linking agent has low reactivity near room temperature and scorch is suppressed.

Further, examples of the filler (C component) used together with the above A component and B component include silica powder, calcium carbonate, alumina, titanium oxide, calcium silicate, zinc oxide, carbon black and the like. In particular, silica powder is preferably used from the viewpoint of reinforcing property. The amount of the filler (C component) compounded is 20 to 20% of the total amount of the matrix material which is the oil swelling layer forming material.
It is preferably set in the range of 80% by weight (hereinafter abbreviated as “%”). It is particularly preferably 30 to 50%. That is, when the compounding amount of the filler is less than 20%, the strength is lowered and wear deterioration becomes remarkable, and when it exceeds 80%, the filler is more exposed on the roll surface and the toner releasability is deteriorated. This is because there is a tendency.

The above oil swelling layer forming material requires a dispersion aid and the like in addition to the above-mentioned main components fluorosilicone rubber (component A), peroxide-based cross-linking agent (component B) and filler (component C). It can be appropriately blended according to.

The fixing roll of the present invention can be manufactured, for example, as follows. That is, first, each coating liquid for forming an oil barrier layer and forming an oil swelling layer is prepared.

The coating liquids for forming the oil barrier layer and the oil swelling layer are prepared as follows. That is, it is prepared by appropriately mixing the constituent components of each forming material, kneading with a roll, a kneader or the like, and adding an organic solvent to this mixture, and mixing and stirring. Then, the concentration of each coating liquid thus prepared is preferably set within a range of, for example, 10 to 50%. It is particularly preferably 15 to 30%.
That is, when the concentration of each coating liquid is less than 10%,
It becomes difficult to obtain a desired predetermined film thickness. In addition, problems such as dripping may occur in the coating process. On the other hand, when it exceeds 50%, the viscosity becomes high and the workability (coating property) deteriorates. Also, as in the above case, there is a tendency that the film thickness becomes thick and a predetermined film thickness cannot be obtained.

Then, as the above-mentioned organic solvent used when a coating liquid is prepared by mixing the above respective components,
There is no particular limitation and a conventionally known one is used. For example, acetone, methyl ethyl ketone (ME
K), ketones such as methyl isobutyl ketone (MIBK), N, N-dimethylformamide (DMF), tetrahydrofuran (THF), polar solvents such as ethyl acetate, and the like.

While preparing each coating liquid as described above, heat was applied to the outer periphery of the metal shaft body by extrusion molding using a material for forming a heat conductivity imparting layer to perform mold vulcanization. A conductivity imparting layer is formed. Then, using each of the coating liquids, first, the coating liquid for forming the oil barrier layer is uniformly applied to the outer peripheral surface of the heat conductivity imparting layer. Then, a coating liquid for forming an oil swelling layer is uniformly applied to the outer periphery of the oil barrier layer and dried, and then heat-crosslinked to form an oil barrier layer and an oil swelling layer. In this way, the desired fixing roll (three-layer structure) as shown in FIG. 1 can be manufactured. FIG.
In the above, 1 is a substantially cylindrical shaft (hollow core metal) having a hollow interior, 2 is a heat conductivity imparting layer, 3 is an oil barrier layer, and 4 is an oil swelling layer.

The coating method of each of the coating liquids for forming the oil barrier layer and the oil swelling layer is not particularly limited, and a conventionally known coating method, for example,
The dipping method, the spray coating method, the roll coating method and the like can be mentioned.

In the fixing roll, the thickness of each layer is preferably set as follows. First, the thickness of the thermal conductivity imparting layer 2 is preferably set in the range of 0.5 to 5 mm, particularly preferably 1 to 3 mm. The thickness of the oil barrier layer 3 is 5 to 50 μm.
It is preferable to set in the range of, and particularly preferably, the thickness is 10 to 20 μm. Furthermore, the thickness of the oil swelling layer 4, which is the outermost layer, is preferably set in the range of 10 to 50 μm, particularly preferably 20 to 30 μm. That is, as a method of fixing the toner to the copy paper by using the fixing roll, a method of heating, pressurizing and pressure bonding is usually adopted. From the viewpoint of the thermal conductivity at the time of heating, pressurizing and pressure bonding, the oil which is the outermost layer is used. The swelling layer 4 is preferably formed as a thin film layer.

[0038]

As described above, in the fixing roll of the present invention, the oil barrier layer is formed on the outer periphery of the heat conductivity imparting layer, and the outermost oil swelling layer is formed on the outer periphery of the oil barrier layer. Further, the oil swelling layer is formed using a matrix forming material containing a fluorosilicone rubber (component A), a peroxide-based cross-linking agent (component B), and a filler (component C), and has a specific range. It is set so that the swelling amount becomes. Therefore, the oil swelling layer swells due to the appropriate absorption of silicone oil to give the toner releasability, and the proper swelling can be set, so that the wear resistance is improved and the durability is improved. The decrease can be prevented.

Next, examples will be described together with comparative examples.

[0040]

Examples 1 to 5 and Comparative Examples 1 and 2 [Formation of heat conductivity imparting layer] An aluminum shaft (cylindrical body) was used as a shaft. On the outer peripheral surface of this aluminum shaft body, a heat conductivity imparting layer forming material comprising the respective components shown in Table 1 below was used, and this was extrusion-molded to perform mold vulcanization.
As a result, a heat conductivity imparting layer having a thickness of 3 mm was formed.

[0041]

[Table 1] * 1: XE20-A7016, manufactured by Toshiba Silicone * 2: TC-8, manufactured by Toshiba Silicone

[Formation of Oil Barrier Layer] Next, the components shown in Table 2 below were blended in the blending ratio shown in the same table and kneaded using a roll. Then, to this mixture, methyl ethyl ketone was added as an organic solvent to a concentration of 15%, mixed and stirred to prepare a coating liquid as an oil barrier layer forming material. Then, the coating liquid was applied to the outer peripheral surface of the heat conductivity imparting layer by a dipping method to form an oil barrier layer having a thickness of 15 μm.

[0043]

[Table 2] *: Viton GBC-900, manufactured by Showa Denko DuPont

[Formation of Oil Swelling Layer] Next, the respective components shown in Table 3 below were blended in the blending ratio shown in the same table and kneaded using a roll. Then, to this mixture was added methyl ethyl ketone as an organic solvent so that the concentration was 15%,
By mixing and stirring, a coating liquid as an oil swelling layer forming material was prepared. Then, the outer peripheral surface of the oil barrier layer is coated with the coating liquid by a dipping method, and then crosslinked by heating in a hot oven (condition: 150 ° C. × 1 hour) to swell the oil with a thickness of 25 μm. Layers were formed.

[0045]

[Table 3]

With respect to the fixing rolls of the respective Examples and Comparative Examples thus obtained, the degree of crosslinking, the swelling amount of silicone oil, the image quality, the abrasion resistance and the durability were measured and evaluated according to the following methods. did. The results are shown in Table 4 below.
Are also shown.

[Crosslinking Degree of Outermost Layer of Fixing Roll] The surface of each fixing roll was wiped with a cloth impregnated with methyl ethyl ketone,
The degree of dissolution of the oil swelling layer, which is the outermost layer, was visually evaluated. As a result, those that did not dissolve at all were indicated as ◯, those that left a wipe mark were indicated as Δ, and those that did dissolve were indicated as x.

[Swelling Amount of Silicone Oil] Each fixing roll was replaced with dimethyl silicone oil (TSF451-35).
0, manufactured by Toshiba Silicone Co., Ltd.) at 160 ° C. for 24 hours. As a result, the swelling amount (ΔW) was calculated by the following formula.

Swelling amount (%) = [(weight after immersion-initial weight) / initial weight] × 100

[Image Quality] Each fixing roll was incorporated in an electrophotographic copying machine, an overhead projector (OHP) sheet was fed, and its winding property was visually observed. As a result, what was wound on the roll was indicated as x, and what was not wound was indicated as o.

[Abrasion resistance] Each fixing roll is incorporated in an electrophotographic copying machine, a separating claw is pressed against the roll surface, and the inner layer is exposed by abrasion of the surface layer in a state where silicone oil is not supplied (abrasion accelerated state). The time required was measured. Then, the time required for exposure within 5 hours is indicated by x, and the time exceeding 5 hours is indicated by o.

[Durability] Each fixing roll is incorporated in an electrophotographic copying machine, copying is performed using a copy paper, and offset (melt toner partially adheres to the roll, and this melt toner adheres to the next copy). The number of copy papers before the occurrence of the phenomenon (transferred as dirt sometimes) occurred was measured and displayed as the offset durable number.

[0053]

[Table 4]

From the results shown in Table 4 above, all the example products were
The swelling amount of the silicone oil was set to an appropriate level, and good results were obtained in all of image quality, abrasion resistance, and durability. In addition, it can be seen that there was no problem in the degree of cross-linking and a fixing roll having sufficient cross-linking was obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a fixing roll of the present invention.

FIG. 2 is a schematic view showing a fixing structure by a heat roll fixing system in an electrophotographic copying machine.

[Explanation of symbols]

 1 shaft 2 thermal conductivity imparting layer 3 oil barrier layer 4 oil swelling layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Yamaguchi 3600 Gyokutsuyama, Komaki City, Aichi Prefecture Totsugu Rubber Industry Co., Ltd.

Claims (1)

[Claims] 1. A fixing in which a heat conductivity imparting layer is formed on the outer periphery of a shaft body, an oil barrier layer is formed on the outer periphery of the heat conductivity imparting layer, and an oil swelling layer is formed on the outer periphery of the oil barrier layer. A swelling amount of the silicone oil in the oil swelling layer is set to 1 to 8% by weight,
A fixing roll characterized in that the oil swelling layer is formed of a matrix material containing the following components (A) to (C). (A) Fluorosilicone rubber. (B) Peroxide type crosslinking agent. (C) Filler.